diff --git a/package.json b/package.json
index 9c9b729..bf5fa7b 100644
--- a/package.json
+++ b/package.json
@@ -27,7 +27,7 @@
   "dependencies": {
     "d": "~0.1.1",
     "es5-ext": "~0.10.7",
-    "es6-weak-map": "~1.0.2",
+    "es6-weak-map": "~0.1.4",
     "event-emitter": "~0.3.3",
     "lru-queue": "0.1",
     "next-tick": "~0.2.2",